Subba Rao s

Initial salary of Subba Rao is Rs. 5000

That is first term (a) = 5000

He receives Rs.200 every year as increment

So, common difference (d) = 200

The year when he reaches Rs. 7000

So, a_n = 7000

a_n = a +(n-1)d

7000 = 5000 + (n-1) 200

2000 = 200(n-1)

10 = n-1

n = 11

So, it takes him 11 years to reach Rs. 7000